Charcoal?
U could fill in the smelter or the butcher (i know his profession is wrong for that, but in my imagination his style would fit into that building )
So i donno if and how u want to change trading prices but nowadays treetrunk to coal is 1:1
So if this shut work it need to be better than trading, so the charcoal should be 1treetrunk for 2coal. But still there is need for timing as it cannot be that the charcoal 2x faster than the coalmine. So the time needed to produce 2coal must be equal to time a coalmine needs to produce 2coal (or might be a little faster as u have additional effort in building woodcutters).
In this way there is the possibility to change ur economy for late game, to woodcutter+charcoal and trading.
What do u think?